Prognostic relevance of TTF-1 and MMP-9 expression in advanced lung adenocarcinoma.

Background: The thyroid transcription factor-1 (TTF-1) is a tissue-specific transcription factor that could play an important role in cell differentiation and morphogenesis of lung tumors. Matrix metalloproteinase-9 (MMP-9) is a protease commonly expressed in non-small cell lung cancer, conferring angiogenic and metastatic potential.

Methods: We assessed TTF-1 and MMP-9 tumor expression by immunohistochemistry in 51 patients with lung adenocarcinoma, stage IIIB or IV, treated with platinum regimens. A bicategorical prognostic model was obtained using the Kaplan-Meier method, Cox regression, and conjunctive consolidation.

Results: The median expression of TTF-1 was 30.0% (range: 0-85.9%). All tumors expressed MMP-9 (median: 78.7%; range: 15.2-96.1%). Median survival was 41.6 weeks, with estimated 1- and 2-year survival rates of 45.0% and 22.0%, respectively. Poor performance status (Karnofsky scale) - hazards ratio (HR): 1.03, 95% confidence interval (CI): 1.01-1.06; low TTF-1 expression (<40%) - HR: 4.00, 95% CI: 1.75-9.09; and high MMP-9 expression (> or =80%) - HR: 2.82, 95% CI: 1.30-6.08 were independent prognostic factors. Patients could be stratified in three death risk groups according to markers expression: low risk (high TTF-1 and low MMP-9; median survival: 127.6 weeks), intermediate risk (low TTF-1 or high MMP-9; median survival: 39.0 weeks); and high risk (low TTF-1 and high MMP-9; median survival: 16.4 weeks).

Conclusion: TTF-1 and MMP-9 tumor expression as detected by immunohistochemistry may allow identification of different, clinically meaningful, prognostic groups of advanced lung adenocarcinoma patients treated with platinum regimens.